Electrically operated smoking device including a system for identifying smoking articles in the device

ABSTRACT

An electrically operated smoking device configured to receive a smoking article is provided, the device including: a housing defining a cavity to at least partially receive the smoking article; and a sensing system to detect indicia on the smoking article, the sensing system being positioned on a periphery of the cavity and including a light source, a mirror, an imaging lens, and an image detector, the mirror being positioned on an internal surface of the cavity adjacent to the light source and the imaging lens.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation application of and claims the benefit of priority under 35 U.S.C. § 120 to U.S. application Ser. No. 15/737,852, filed Dec. 19, 2017, which is a U.S. National Stage Application of PCT/EP2016/067887, filed Jul. 27, 2016, and claims benefit of priority under 35 U.S.C. § 119 to European Patent Application No. 15181074.4, filed on Aug. 14, 2015, the entire contents of each of which are incorporated herein by reference.

TECHNICAL FIELD

The present invention relates to electrically operated smoking devices which receive smoking articles in use. In particular, the invention relates to electrically operated smoking devices that are able to recognise a smoking article inserted into the device by imaging indicia on the smoking article.

DESCRIPTION OF THE RELATED ART

A number of prior art documents, such as U.S. Pat. Nos. 5,060,671A, 5,388,594 and 5,505,214, disclose electrically operated smoking systems that heat rather than burn an aerosol-forming substrate. These systems operate to heat the substrate to a temperature at which desirable volatile compounds are released but maintain the temperature below a temperature at which combustion might occur.

Because the flavours are generated and released by a controlled heating of the aerosol-forming substrate, without the combustion that takes place in lit-end cigarettes, smoking articles developed for electrically heated smoking systems are typically specially designed for a particular smoking system. The structure of a smoking article designed for an electrically heated smoking system is typically different from the structure of a lit-end smoking article. Using a lit-end smoking article with an electrically heated smoking system may result in a poor smoking experience for the user, and may also damage the system. For example, the smoking article may not be compatible with the system because it has insufficient moisture content. In addition, there may be a number of different smoking articles which are each configured for use with the system, but which each provide a different smoking experience for the user and may require heating to a different temperature.

Counterfeiting of smoking articles is also a problem. Counterfeit smoking articles may be of inferior quality or may not be suited to a smoking system at all.

There is therefore a need for a smoking system that is able to identify smoking articles that are suitable or unsuitable for use with the smoking system. However, although it is desirable that the system identifies and does not operate with unsuitable smoking articles, it also important that the smoking system does not erroneously reject articles that are suitable for use with the system. Users would quickly become dissatisfied with a system that frequently rejects correct smoking articles.

WO2010/073122 discloses a system in which indicia, such as a printed barcode, on the smoking article are sensed by an optical sensor in order to distinguish between different smoking articles.

However, it is desirable that any sensing system of the type described in WO2010/073122 does not significantly impact the size of the smoking system, the power consumption of the smoking system or the cost of the smoking system. At the same time the sensing system must be reliable and have sufficient resolving power to recognize printed patterns on small smoking articles. And the fact that smoking articles tend to be shaped like lit-end cigarettes, means that the indicia are marked on a curved surface. This makes imaging the pattern more difficult.

SUMMARY

It is an object of the invention to provide a smoking device with a sensing system that is able to identify smoking articles, that is compact and has low power consumption but that is reliable and minimizes false rejection of correct smoking articles.

In a first aspect of the invention, there is provided an electrically operated smoking device configured to receive a smoking article, comprising:

a housing defining a cavity for at least partially receiving a smoking article; and

a sensing system for detecting indicia on the smoking article, the sensing system positioned on a periphery of the cavity and comprising a light source, a mirror, an imaging lens and an image detector, wherein the mirror is positioned on an internal surface of the cavity adjacent to the light source and the imaging lens.

BRIEF DESCRIPTION OF THE DRAWINGS

Examples of the invention will now be described in detail with reference to the accompanying drawings, in which:

FIG. 1 is a schematic diagram of an aerosol generating device;

FIG. 2 is a cross section of a front end of a device of the type shown in FIG. 1;

FIG. 3 is a cross section of a front end of a device of the type shown in FIG. 1, incorporating a smoking article imaging system in accordance with the invention;

FIG. 4 is a schematic perspective view of the imaging components of a device in accordance with the invention; and

FIG. 5 is a cross-section of the imaging components of an embodiment of the invention.

DETAILED DESCRIPTION

The provision of a mirror on an internal surface of the cavity allows for a wide field of view to be imaged in a small space. A mirror also provides for optical efficiency.

As used herein, the term “mirror” means a surface that is optically reflective, and in particular that specularly reflects light from the light source. The mirror may be provided as an optically reflective coating.

The cavity may be cylindrical and may have an open end through which the smoking article is received. The cavity may have a base at an opposite end to the open end. The lens and image detector may be positioned at the base of the cavity. The light source may also be placed at the base of the cavity. The mirror may extend along a surface of the cavity extending between the open end and the base end. It may be desirable for the device to have an elongate shape, having a length much greater than a diameter. It may be desirable for the device to have a diameter close to the diameter of a lit-end cigarette, and not much greater than the diameter of the smoking article. The device may be configured so that the smoking article is inserted into the cavity in in a lengthwise direction. This arrangement of the image detector and mirror allows the image detector, and the associated electronics to be in a position that does not increase a diameter of the device.

The light source may be configured to emit light at an oblique angle to an optical axis of the lens. This improves the illumination in the centre of the field of view of the resulting image.

The light source may comprise an LED. The light source may include a light guide positioned to deflect light emitted from the LED. The light guide may deflect light towards an optical axis of the lens. This may improve illumination of a resulting image captured by the detector.

The light source may comprise more than one LED. The provision of two or more separate sources of light may improve the homogeneity of the illumination of the smoking article and of resulting images captured by the detector.

The light source and the detector may be provided on a single circuit board. This provides for a compact system. An opaque shield structure may be provided between the light source and the image detector. The shield structure may prevent light from the light source directly entering the image detector, without first being reflected by the smoking article.

The shield structure may be provided between the light source and the lens and between any light guides and the lens. In one embodiment, the lens is provided in an aperture of the shield structure. The light guides may also be provided in apertures in the shield structure. The shield structure may include one or more spacer elements to support the lens a desired distance from the detector. The spacer element may be opaque to light from the light source.

The image detector may be a detector capable of forming an image of the indicia. The image detector may be a CMOS or CCD based detector.

The device may comprise a sliding receptacle that receives the smoking article in use and that can be moved towards the open end of the cavity when a smoking article is to be removed. The sliding receptacle reduce the risk of the smoking article breaking during removal from the cavity. The mirror may be provided on a surface of the sliding receptacle. The sliding receptacle may comprise an aperture positioned to allow for light from the light source to reach the mirror and the smoking article. The same or a different aperture in the sliding receptacle may allow light from the mirror and smoking article to reach the lens. Alternatively, some or all of the sliding receptacle may be transparent to allow light from the light source to reach the mirror and the smoking article and return to the image detector.

The cavity or sliding receptacle may be shaped to provide a channel between the mirror and a smoking article when the smoking article is received in the cavity. The channel allows for light from the light source to reach a portion of the smoking article that is to be imaged.

The device may include an aerosol-generating element that interacts with the smoking article to produce an aerosol. The aerosol-generating element may be a heater configured to heat a smoking article when the smoking article is in the cavity. The heater may comprise an electrically resistive material. Suitable electrically resistive materials include but are not limited to: semiconductors such as doped ceramics, electrically “conductive” ceramics (such as, for example, molybdenum disilicide), carbon, graphite, metals, metal alloys and composite materials made of a ceramic material and a metallic material. Such composite materials may comprise doped or undoped ceramics. Examples of suitable doped ceramics include doped silicon carbides. Examples of suitable metals include titanium, zirconium, tantalum platinum, gold and silver. Examples of suitable metal alloys include stainless steel, nickel-, cobalt-, chromium-, aluminium-titanium-zirconium-, hafnium-, niobium-, molybdenum-, tantalum-, tungsten-, tin-, gallium-, manganese-, gold- and iron-containing alloys, and super-alloys based on nickel, iron, cobalt, stainless steel, Timetal® and iron-manganese-aluminium based alloys. In composite materials, the electrically resistive material may optionally be embedded in, encapsulated or coated with an insulating material or vice-versa, depending on the kinetics of energy transfer and the external physicochemical properties required.

The heater may comprise an internal heating element or an external heating element, or both internal and external heating elements, where “internal” and “external” refer to the smoking article. An internal heating element may take any suitable form. For example, an internal heating element may take the form of a heating blade. The heating blade may be formed from a ceramic substrate with one or more resistive heating tracks, formed from platinum or another suitable material, deposited on one or both sides of the blade. Alternatively, the internal heater may take the form of a casing or substrate having different electro-conductive portions, or an electrically resistive metallic tube. Alternatively, the internal heating element may be one or more heating needles or rods that run through the centre of the aerosol-forming substrate. Other alternatives include a heating wire or filament, for example a Ni—Cr (Nickel-Chromium), platinum, tungsten or alloy wire or a heating plate. Optionally, the internal heating element may be deposited in or on a rigid carrier material. In one such embodiment, the electrically resistive heating element may be formed using a metal having a defined relationship between temperature and resistivity. In such an exemplary device, the metal may be formed as a track on a suitable insulating material, such as ceramic material, and then sandwiched in another insulating material, such as a glass. Heaters formed in this manner may be used to both heat and monitor the temperature of the heating elements during operation.

An external heating element may take any suitable form. For example, an external heating element may take the form of one or more flexible heating foils on a dielectric substrate, such as polyimide. The flexible heating foils can be shaped to conform to the perimeter of the cavity. Alternatively, an external heating element may take the form of a metallic grid or grids, a flexible printed circuit board, a moulded interconnect device (MID), ceramic heater, flexible carbon fibre heater or may be formed using a coating technique, such as plasma vapour deposition, on a suitable shaped substrate. An external heating element may also be formed using a metal having a defined relationship between temperature and resistivity. In such an exemplary device, the metal may be formed as a track between two layers of suitable insulating materials. An external heating element formed in this manner may be used to both heat and monitor the temperature of the external heating element during operation. The sliding receptacle may comprise a heating aperture to allow for contact between an external heating element and a smoking article in the cavity.

The heater advantageously heats the smoking article by means of conduction. The heater may be at least partially in contact with the substrate. Alternatively, the heat from either an internal or external heating element may be conducted to the substrate by means of a heat conductive element.

The device may comprise control circuitry for comparing image data from the image detector with stored image data. The control circuitry may connected with the image detector. The control circuitry may also be connected to the heater or to another aerosol-generating element. The control circuitry may control a supply of power to the aerosol-generating element dependent on the outcome of a comparison between image data from the image detector and stored image data. For example, if the image data from the image detector does not sufficiently correlate with stored image data, then the control circuitry may prevent the supply of power to the aerosol-generating element. If the image data from the image detector does sufficiently correlate with stored image data, the control circuitry may allow the supply of power to the aerosol-generating element. In other words, based on an image comparison, the control circuitry may identify if a legitimate smoking article is present in the cavity and may allow the device to operate only when a legitimate smoking article is determined to be present in the cavity. The control circuitry may operate a particular power control process depending on which stored image data the image data from the image detector most strongly correlates to. In other words, based on an image comparison, the control circuitry may identify a particular type of smoking article and may control the device in a manner that is appropriate for that smoking article. For example, different smoking articles may advantageously be heated to different temperatures to produce a desirable aerosol.

The control circuitry may comprise one or more microcontrollers. Each or the one or more microcontrollers may comprise a microprocessor, and advantageously comprises a programmable microprocessor. The control circuitry may comprise a non-volatile memory. The device may comprise an interface configured to allow for the transfer of data to and from the control circuitry from external devices. The interface may allow for the uploading of software to the control circuitry to run on the programmable microprocessor. The interface may be a wired interface, such as a micro USB port, or may be a wireless interface.

The aerosol-generating device may further comprise a power supply for supplying power to the aerosol-generating element. The power supply may be any suitable power supply, for example a DC voltage source. In one embodiment, the power supply is a Lithium-ion battery. Alternatively, the power supply may be a Nickel-metal hydride battery, a Nickel cadmium battery, or a Lithium based battery, for example a Lithium-Cobalt, a Lithium-Iron-Phosphate, Lithium Titanate or a Lithium-Polymer battery.

The smoking device is preferably a handheld aerosol-generating device that is comfortable for a user to hold between the fingers of a single hand. The smoking device may be substantially cylindrical in shape. The smoking device may have a length between about 70 mm and 120 mm. The smoking device may have a diameter between about 10 mm and 20 mm.

In a second aspect of the invention there is provided a smoking system comprising a device in accordance with a first aspect of the invention and a smoking article.

The smoking article may comprise indicia or markings on an outer surface of the smoking article. The indicia may be a pattern, such as a checkerboard pattern. Alternatively, the indicia may comprise a one dimensional barcode or a two dimensional barcode. The indicia may extend fully around a perimeter of the smoking article.

The smoking article may be substantially cylindrical in shape. The smoking article may be substantially elongate. The smoking article may have a length and a circumference substantially perpendicular to the length. The smoking article may comprise an aerosol-forming substrate. The aerosol-forming substrate may be substantially cylindrical in shape. The aerosol-forming substrate may be substantially elongate. The aerosol-forming substrate may also have a length and a circumference substantially perpendicular to the length.

The smoking article may have a total length between approximately 30 mm and approximately 100 mm. The smoking article may have an external diameter between approximately 5 mm and approximately 12 mm. The smoking article may comprise a filter plug. The filter plug may be located at the downstream end of the smoking article. The filter plug may be a cellulose acetate filter plug. The filter plug is approximately 7 mm in length in one embodiment, but may have a length of between approximately 5 mm to approximately 10 mm.

In one embodiment, the smoking article has a total length of approximately 45 mm. The smoking article may have an external diameter of approximately 7.2 mm. Further, the aerosol-forming substrate may have a length of approximately 10 mm. Alternatively, the aerosol-forming substrate may have a length of approximately 12 mm. Further, the diameter of the aerosol-forming substrate may be between approximately 5 mm and approximately 12 mm. The smoking article may comprise an outer paper wrapper. The indicia may be on the outer paper wrapper. The indicia may be printed on the outer paper wrapper. Further, the smoking article may comprise a separation between the aerosol-forming substrate and the filter plug. The separation may be approximately 18 mm, but may be in the range of approximately 5 mm to approximately 25 mm. The separation is preferably filled in the smoking article by a heat exchanger that cools the aerosol as it passes through the smoking article from the substrate to the filter plug. The heat exchanger may be, for example, a polymer based filter, for example a crimped PLA material.

The aerosol-forming substrate may be a solid aerosol-forming substrate. Alternatively, the aerosol-forming substrate may comprise both solid and liquid components. The aerosol-forming substrate may comprise a tobacco-containing material containing volatile tobacco flavour compounds which are released from the substrate upon heating. Alternatively, the aerosol-forming substrate may comprise a non-tobacco material. The aerosol-forming substrate may further comprise an aerosol former. Examples of suitable aerosol formers are glycerine and propylene glycol.

If the aerosol-forming substrate is a solid aerosol-forming substrate, the solid aerosol-forming substrate may comprise, for example, one or more of: powder, granules, pellets, shreds, spaghettis, strips or sheets containing one or more of: herb leaf, tobacco leaf, fragments of tobacco ribs, reconstituted tobacco, homogenised tobacco, extruded tobacco, cast leaf tobacco and expanded tobacco. The solid aerosol-forming substrate may be in loose form, or may be provided in a suitable container or cartridge. Optionally, the solid aerosol-forming substrate may contain additional tobacco or non-tobacco volatile flavour compounds, to be released upon heating of the substrate. The solid aerosol-forming substrate may also contain capsules that, for example, include the additional tobacco or non-tobacco volatile flavour compounds and such capsules may melt during heating of the solid aerosol-forming substrate.

As used herein, homogenised tobacco refers to material formed by agglomerating particulate tobacco. Homogenised tobacco may be in the form of a sheet. Homogenised tobacco material may have an aerosol-former content of greater than 5% on a dry weight basis. Homogenised tobacco material may alternatively have an aerosol former content of between 5% and 30% by weight on a dry weight basis. Sheets of homogenised tobacco material may be formed by agglomerating particulate tobacco obtained by grinding or otherwise comminuting one or both of tobacco leaf lamina and tobacco leaf stems. Alternatively, or in addition, sheets of homogenised tobacco material may comprise one or more of tobacco dust, tobacco fines and other particulate tobacco by-products formed during, for example, the treating, handling and shipping of tobacco. Sheets of homogenised tobacco material may comprise one or more intrinsic binders, that is tobacco endogenous binders, one or more extrinsic binders, that is tobacco exogenous binders, or a combination thereof to help agglomerate the particulate tobacco; alternatively, or in addition, sheets of homogenised tobacco material may comprise other additives including, but not limited to, tobacco and non-tobacco fibres, aerosol-formers, humectants, plasticisers, flavourants, fillers, aqueous and non-aqueous solvents and combinations thereof.

Optionally, the solid aerosol-forming substrate may be provided on or embedded in a thermally stable carrier. The carrier may take the form of powder, granules, pellets, shreds, spaghettis, strips or sheets. Alternatively, the carrier may be a tubular carrier having a thin layer of the solid substrate deposited on its inner surface, or on its outer surface, or on both its inner and outer surfaces. Such a tubular carrier may be formed of, for example, a paper, or paper like material, a non-woven carbon fibre mat, a low mass open mesh metallic screen, or a perforated metallic foil or any other thermally stable polymer matrix.

The solid aerosol-forming substrate may be deposited on the surface of the carrier in the form of, for example, a sheet, foam, gel or slurry. The solid aerosol-forming substrate may be deposited on the entire surface of the carrier, or alternatively, may be deposited in a pattern in order to provide a non-uniform flavour delivery during use.

Although reference is made to solid aerosol-forming substrates above, it will be clear to one of ordinary skill in the art that other forms of aerosol-forming substrate may be used with other embodiments. For example, the aerosol-forming substrate may be a liquid aerosol-forming substrate. If a liquid aerosol-forming substrate is provided, the aerosol-generating device preferably comprises means for retaining the liquid. For example, the liquid aerosol-forming substrate may be retained in a container. Alternatively or in addition, the liquid aerosol-forming substrate may be absorbed into a porous carrier material. The porous carrier material may be made from any suitable absorbent plug or body, for example, a foamed metal or plastics material, polypropylene, terylene, nylon fibres or ceramic. The liquid aerosol-forming substrate may be retained in the porous carrier material prior to use of the aerosol-generating device or alternatively, the liquid aerosol-forming substrate material may be released into the porous carrier material during, or immediately prior to use. For example, the liquid aerosol-forming substrate may be provided in a capsule. The shell of the capsule preferably melts upon heating and releases the liquid aerosol-forming substrate into the porous carrier material. The capsule may optionally contain a solid in combination with the liquid.

Alternatively, the carrier may be a non-woven fabric or fibre bundle into which tobacco components have been incorporated. The non-woven fabric or fibre bundle may comprise, for example, carbon fibres, natural cellulose fibres, or cellulose derivative fibres.

In FIG. 1, the components of an embodiment of an electrically heated smoking device 100 are shown in a simplified manner. Particularly, the elements of the electrically heated smoking device 100 are not drawn to scale in FIG. 1. Elements that are not relevant for the understanding of this embodiment have been omitted to simplify FIG. 1.

The electrically heated smoking device 100 comprises a housing 10 and an aerosol-forming substrate 12 in a smoking article, for example a cigarette. The aerosol-forming substrate 12 is pushed inside a cavity in the housing 10 to come into thermal proximity with the heating element 14. The aerosol-forming substrate 12 will release a range of volatile compounds at different temperatures. By controlling the maximum operation temperature of the electrically heated smoking device 100 to be below the release temperature of some of the volatile compounds, the release or formation of these smoke constituents can be avoided.

Within the housing 10 there is an electrical energy supply 16, for example a rechargeable lithium ion battery. A microcontroller 18 is connected to the heating element 14, the electrical energy supply 16, and a user interface 20, for example a button or a display, or both a button and a display. The microcontroller 18 has embedded software to control the power supplied to the heating element 14 in order to regulate its temperature. Typically the aerosol-forming substrate is heated to a temperature of between 250 and 450 degrees centigrade. An image sensing module 40 is also connected to the microcontroller, as will be described. The microcontroller 18 controls the power supplied to the heating element dependent on the data from the image sensing module following insertion of a smoking article into the device, as will be described.

FIG. 2 is a cross-section view of a front end of a device of the type shown in FIG. 1, without a sensing module. A smoking article 12 is received in a cavity 15 in the device. The heater 14 is a ceramic blade which is positioned within the aerosol-forming substrate when the smoking article is received in the cavity 15. The housing 10 has a fixed portion 22 and a front portion 24 which is able to slide relative to the fixed portion. The heater is fixed to a support 20, which is fixed to the fixed portion of the housing 22. The front portion 24 forms a sliding receptacle into which the smoking article is received. The front portion includes a rear surface 26 between the smoking article and the heater support 20. By sliding the front portion away from the fixed portion, towards the open end of the cavity, the smoking article is pulled off the heater 14 by the rear surface 26 and so can be removed from the device easily.

The device shown in FIGS. 1 and 2 is generally cylindrical and elongate so that it can be held easily in one hand, in the same manner as a lit-end cigarette. It is desirable that the device is only marginally wider than the smoking article. Because of that, space for a sensor system for recognising markings on the smoking article is very limited in the front end of the device around the smoking article. It can be seen from FIG. 2 in particular that there is very little space for an imaging system that would provide sufficient optical resolution to distinguish different markings on a smoking article.

FIG. 3 is a cross-section view of a front end of a device of the type shown in FIG. 1, with a sensing system in accordance with the invention. The sensing system takes up very little space in the device and does not increase the diameter of the device, but does allow for the capture of an image over a wide area of the smoking article.

The sensing system comprises a sensor module 40 and a mirror 36 formed on an inside surface of the front housing 34. The sensor module comprises a pair of light emitting diodes (LEDs) for illuminating the surface of the smoking article and the mirror and an imaging lens and image detector for recording an image of the surface of the smoking article 12. The sensing module is positioned on the support 20 on a base end of the cavity. An aperture in the front housing allows light from the sensing module to reach the smoking article and for light reflected from the smoking article 12 and the mirror 36 to return to the sensing module. The mirror 36 is formed by a reflective coating on an interior surface of the front housing. The mirror is formed on a recessed portion of the housing so that there is a channel 38 between the mirror 36 and the surface of the smoking article. This allows for an image of a significant portion of the surface of the smoking to be obtained. The use of a single lens provides a large aperture. The image detector can be made relatively large as it is positioned at the base of the cavity rather than on the side of the cavity. This provides images with high resolution and high optical efficiency. The front portion of the housing may comprise a plurality of mirrors to allow the front portion of the housing to be fitted to the fixed housing in a plurality of different orientations without preventing the sensing system from operating correctly.

FIG. 4 is a schematic illustration of the sensing system. In FIG. 4 shows the light source 42 emitting light into the channel 38 between the surface of the smoking article and the mirror. The surface of the smoking article has a printed pattern 13 that represents the type of smoking article it is. A lens 44 and image detector 46 are arranged adjacent the light source 42. The light source is arranged to emit light at an oblique angle to the optical axis of the lens and to the detector. This has been found to improve the illumination in the centre of the captured image.

It is advantageous to provide the light source, lens and image detector in a single module, as illustrated in FIG. 3. FIG. 5 is a cross-sectional illustration of an exemplary sensing module adjacent a mirror 36 and smoking article 12. The sensing module comprises a pair of LEDs 42 arranged on either side of an image detector 46. In this example the image detector is a complementary metal oxide semiconductor (CMOS) image detector, but it may be a CCD detector. The image detector 46 and LEDs are mounted on the same printed circuit board 54. The lens 44 is provided in a shielding structure 50. The shielding structure 50 is opaque and is glued onto the circuit board 54. The shielding structure includes opaque spacer elements 52 that provide the required spacing between the lens 44 and the image detector 46. The shielding structure also includes apertures for light guides 48 that deflect light emitted by the LEDs to an angle oblique to the optical axis of the lens. This arrangement provides a robust and compact structure. A sensing module arranged in this way, requiring only two LEDS, consumes relatively little power, which is important in a handheld smoking system with limited battery capacity.

It is important that the materials used in the sensing module are able to withstand the large changes in temperature that occur with in the cavity of the device. It is also important that the optical performance of the module does not significantly deteriorate at high temperatures. In this example the housing components are formed from polyether ether ketone (PEEK) and the optical components are formed from a polycarbonate material.

The indicia on the smoking article are printed on the outer wrapper paper. The wrapper paper is white. The indicia may simply be black markings on the paper, but in a preferred embodiment the indicia include different grey levels. Different grey levels can be generated by varying the dose of ink or by printing in dots that are smaller than the minimum feature size resolvable by the sensing module. The indicia may be a one dimension barcode, with each line in the barcode extending around the perimeter of smoking article so that it can be placed in the cavity in any orientation. Alternatively, a two dimensional barcode may be used, and the microcontroller in the device may include software that is able to determine where the barcode starts and finishes.

The inks used to make the indicia must correspond to the LEDs used in the sensor module. So if the LEDs emit infrared (IR) light, the inks have to be absorb IR light. Equally the lens has to match the wavelength of the light from the LEDs.

The sensing module is connected to a microcontroller 18 in the device, as illustrated in FIG. 1. The microcontroller includes software for correlating image data from the image detector with stored image data relating to one or more types of acceptable smoking articles. Following activation of the device by a user, the microcontroller activates the image sensing module and the image sensing module captures an image of the smoking article in the cavity. The captured image is sent to the microcontroller as image data. The microcontroller 18 correlates the image data with the stored image data relating to one or more types of acceptable smoking articles. If the captured image data does not correlate sufficiently with stored image data then the microcontroller prevents the supply of power to the heater. If the captured image data does correlate sufficiently with stored image data, then the microcontroller permits the supply of power to the heater. The microcontroller may control the power to the heater so that the heater follows a particular temperature profile or power profile, depending on which stored image data the captured image data most strongly correlates to.

It should be clear that, the exemplary embodiments described above illustrate but are not limiting. In view of the above discussed exemplary embodiments, other embodiments consistent with the above exemplary embodiments will now be apparent to one of ordinary skill in the art. 

1.-15. (canceled)
 16. An electrically operated smoking device configured to receive a smoking article, comprising: a housing defining a cavity configured to at least partially receiving a smoking article; and a sensing system configured to detect indicia on the smoking article, the sensing system positioned on a periphery of the cavity and comprising a light source, a mirror, an imaging lens, and an image detector, wherein the mirror is positioned on an internal surface of the cavity adjacent to the light source and the imaging lens, and wherein an opaque shield structure is positioned between the light source and the image detector.
 17. The electrically operated smoking device according to claim 16, wherein the light source comprises an LED and a light guide positioned to deflect light emitted from the LED towards an optical axis of the imaging lens.
 18. The electrically operated smoking device according to claim 16, further comprising a sliding receptacle configured to receive the smoking article and to be moved towards an open end of the cavity when a smoking article is to be removed, wherein the mirror is positioned on a surface of the sliding receptacle.
 19. An electrically operated smoking device configured to receive a smoking article, comprising: a housing defining a cavity configured to at least partially receiving a smoking article; and a sensing system configured to detect indicia on the smoking article, the sensing system positioned on a periphery of the cavity and comprising a light source, a mirror, an imaging lens, and an image detector, wherein the mirror is positioned on an internal surface of the cavity adjacent to the light source and the imaging lens, and wherein the mirror is an optically reflective coating.
 20. The electrically operated smoking device according to claim 19, wherein the light source is configured to emit light at an oblique angle to an optical axis of the imaging lens.
 21. The electrically operated smoking device according to claim 19, wherein the light source comprises an LED and a light guide positioned to deflect light emitted from the LED towards an optical axis of the imaging lens.
 22. The electrically operated smoking device according to claim 19, wherein the light source and the detector are provided on a single circuit board.
 23. The electrically operated smoking device according to claim 19, further comprising a sliding receptacle configured to receive the smoking article and to be moved towards an open end of the cavity when a smoking article is to be removed, wherein the mirror is positioned on a surface of the sliding receptacle.
 24. An electrically operated smoking device configured to receive a smoking article, comprising: a housing defining a cavity configured to at least partially receiving a smoking article; and a sensing system configured to detect indicia on the smoking article, the sensing system positioned on a periphery of the cavity and comprising a sensor module and a mirror, the sensor module comprising a light source, an imaging lens, and an image detector, wherein the mirror is positioned on an internal surface of the cavity adjacent to the sensor module.
 25. The electrically operated smoking device according to claim 24, wherein the cavity has an open end through which the smoking article is received and a base at an opposite end to the open end, and wherein the sensor module is positioned at the base of the cavity.
 26. The electrically operated smoking device according to claim 25, wherein the mirror extends along a surface of the cavity extending between the open end and the base end.
 27. The electrically operated smoking device according to claim 24, wherein the light source is configured to emit light at an oblique angle to an optical axis of the imaging lens.
 28. The electrically operated smoking device according to claim 24, wherein the light source comprises an LED and a light guide positioned to deflect light emitted from the LED towards an optical axis of the imaging lens.
 29. The electrically operated smoking device according to claim 24, wherein the light source comprises a plurality of LEDs.
 30. The electrically operated smoking device according to claim 24, wherein the light source and the detector are provided on a single circuit board.
 31. The electrically operated smoking device according to claim 24, further comprising an opaque shield structure between the light source and the detector.
 32. The electrically operated smoking device according to claim 31, wherein the opaque shield structure is disposed between the light source and the lens.
 33. The electrically operated smoking device according to claim 31, wherein the imaging lens is provided in an aperture of the opaque shield structure.
 34. The electrically operated smoking device according to claim 24, further comprising a sliding receptacle configured to receive the smoking article and to be moved towards an open end of the cavity when a smoking article is to be removed, wherein the mirror is positioned on a surface of the sliding receptacle.
 35. The electrically operated smoking device according to claim 34, wherein the cavity or sliding receptacle is shaped to provide a channel between the mirror and a smoking article when the smoking article is received in the cavity. 